This definitely does seem like the beginning of a story and not a completed one. The thing I find most interesting is how different the two characters act. If you ever did write the story you had planned, I think it would be interesting what Sango and Soujiro learn from each other. They are different but don't have conflicting, or abrasive, personalities.

What happened to the story you had planned for these two? Just not enough time to write it? Or not enough interest in it?